超临界水稠油改质反应动力学研究

Supercritical water upgrading of heavy oil has the advantages of fast speed and inhibition of coking. In this paper, the effects of reaction temperature 380∼440^◦C and reaction time 0∼500 min on supercritical water upgrading of heavy oil were investigated. The experimental results showed that the process of supercritical water upgrading of heavy oil possessed three stages: the induction stage, the cracking stage and the gas-generation stage. The cracking of resins is significant and no coke formed in the induction stage. In the cracking stage, heavy components were continuously cracking, producing a large amount of light components. In the gas-generation stage, the secondary cracking of saturates produced gas. Meanwhile, the process of supercritical water upgrading of heavy oil was accelerated with the increase of the reaction temperature. Based on the phase separation kinetics, six-lump reaction kinetic model was developed. The solubility coefficient of asphaltenes decreased as temperatures increased, and the dispersion effect of maltenes to asphaltenes weakened at higher temperature. The method of reaction kinetics is helpful to explain the reaction paths and mechanism of supercritical water upgrading of heavy oil.